It sounds like a great idea: David Mamet, the playwright famous for brutal dialogue ("Glengarry Glen Ross") and fiendish plot twists ("House of Games"), brings his formidable brain to the usually brainless genre of martial-arts action flicks. All the usual Mametian ingredients are here -- con-men, magic tricks, the cauliflower-nosed actor Ricky Jay -- but there's also the promise of the visual excitement that comes when men pummel each other on screen.

"Redbelt" fails on nearly every level, from its incoherent story line to its threadbare action sequences. Chiwetel Ejiofor ("American Gangster") stars as Mike Terry, a jiu-jitsu teacher with a samurai's composure: He uses his skills only reluctantly. But after he's conned by an aging action star (Tim Allen) and a sleazy movie producer (Joe Mantegna), he must enter a mixed martial-arts competition to make everything right. You've seen teen breakdancing flicks with better plots, and cooler acrobatics, than this.

For Mamet, who in recent years began studying jiu-jitsu, "Redbelt" surely has some personal resonance and inner logic. For the rest of us, it's proof that even the most assured filmmaker can fall flat on his face.